Prior to the present invention, a check valve of this kind has been taught in the prior art. This check valve serves the purpose of assuring the user that pressurized pipes are not inadvertently emptied of pressurized fluid. The pressure medium is expected to flow in only one direction. In many applications, the pressure medium is prevented from being recirculated by the check valve which automatically closes the inlet when the pressure in the feed line decreases. When the pressure increases in the feed line, the spring in the check valve permits the opening of the inlet so that an equilibrium of pressure can be established in the pressurized pipes.
Depending on the particular operational conditions of the system, flowing media may carry impurities through the piping. These impurities in the media may lead to the occurrence of detrimental deposits at points where the flow behavior is impaired, such as in the labyrinth of a check valve. Such deposits in the check valve can lead to the failure of moving valve components. The conventional method used in the prior art for trying to prevent this phenomenon consists of constructing the check valve in such a way that the bearings and guides of the moving valve components, as for example, those of the valve body of the check valve mentioned above, are fitted with as much play as is feasibly possible.
The primary advantage of the decrease in the susceptance to failure of the check valve which has been achieved by the designing of the play in such check valve as described above is, however, accompanied by the significant disadvantage that unavoidable swirling of the media flowing through the check valve labyrinth, along with the elasticity of the valve spring, by its effect on the valve body, can easily cause the valve body to oscillate in a detrimental manner. In addition, this usually results in undesirable valve noises, which can assume differing pitch of differing intensity. These valve noises depend, to a large extent, on the oscillation frequency of the check valve, the flow rate of the media through such check valve, and the particular shape of the interior of the housing of such check valve.